1. Field of the Invention
The present invention relates to a novel acylacetamide-based yellow dye-forming coupler and a silver halide color photographic light-sensitive material containing this yellow dye-forming coupler.
2. Description of the Related Art
When a silver halide color photographic light-sensitive material is exposed and developed, an oxidized aromatic primary amine developing agent reacts with a dye-forming coupler (to be referred to as a coupler hereinafter), thereby forming a dye image.
In this method, a color reproduction technique using subtractive color processes is generally used. In order to reproduce blue, green, and red, dye images of yellow, magenta, and cyan, which are complementary colors of blue, green, and red, respectively, are formed. An acylacetamide coupler and a malondianilide coupler are used as yellow dye-forming couplers (to be referred to as yellow couplers hereinafter) to form a yellow dye image. A 5-pyrazolone coupler, a pyrazolotriazole coupler, and the like are generally used as magenta couplers to form a magenta dye image. A phenol coupler and a naphthol coupler are generally used as cyan couplers to form a cyan dye image.
Yellow, magenta, cyan dyes obtained from these couplers are generally used in silver halide emulsion layers which have sensitivities to radiations having a relationship of complementary colors with radiations absorbed by these dyes and their adjacent layers.
As the yellow coupler, especially image formation couplers, an acylacetamide coupler represented by a benzoylacetanilide coupler or a pivaloylacetanilide coupler is generally used. The former coupler has a high coupling activity with an aromatic primary amine developing agent and can produce a yellow dye having a large molecular absorption coefficient. Therefore, this coupler is mainly used in a photographic color light-sensitive material for photographing which needs high sensitivity and, particularly, a color negative film. The latter coupler is excellent in spectral absorption characteristics and dye fastness and is therefore mainly used in color paper and a color reversal film.
The benzoylacetanilide-based coupler has a high coupling reactivity with the oxidized form of an aromatic primary amine developing agent during development and can produce a yellow azomethine dye having a large molecular absorption coefficient. However, the benzoylacetanilide-based coupler is poor in spectral absorption characteristics of a yellow image. The pivaloylacetanilide-based coupler is excellent in spectral absorption characteristics and fastness of the yellow image. However, this coupler is poor in coupling reactivity with the oxidized form of an aromatic primary amine developing agent during development. In addition, the resultant yellow azomethine dye of the coupler has a problem of a small molecular absorption coefficient.
The high coupling reactivity of a coupler and the large molecular absorption coefficient of the resultant dye allow a high sensitivity, a large gamma value, and a high color density to so-called improved color forming properties. The excellent spectral absorption characteristics in the yellow image indicate, for example, good sharpness in the long-wavelength limit in spectral absorption, and less unnecessary absorption in green region.
A strong demand, therefore, has arisen for a yellow coupler having both the advantages, i.e., improved color forming properties (i.e., a high coupling reactivity of the coupler and a large molecular absorption coefficient of the resultant dye), and excellent spectral absorption characteristics and fastness of the resultant color image.
Examples of the acyl group of the acylacetanilide-based coupler are pivaloyl, 7,7-dimethylnorbornane-1-carbonyl, and 1-methylcyclohexane-1-carbonyl disclosed in U.S. Pat. No. Re. 27,848, cyclopropane-1-carbonyl and cyclohexane-1-carbonyl disclosed in JP-A-47-26133 ("JP-A" means Published Unexamined Japanese Patent Application), and adamantane-1-carbonyl disclosed in JP-A-56-87041. Each of these couplers, however, is unsatisfactory in any of coupling reactivity, a molecular absorption coefficient, or spectral absorption characteristics or fastness of the resultant dye image.
Recent photographic light-sensitive materials are required to have a higher sensitivity, a better image quality, and a higher toughness more eagerly than before. Accordingly, a strong demand has arisen for a coupler superior in color forming properties, and spectral absorption characteristics and fastness of the resultant dye image. However, it is difficult for the conventional yellow couplers including those described in the above three prior-art inventions to satisfy all these requirements at the same time.